Actuating means for microswitches



Aug. 2, 1966 O. KRAUSS ET L ACTUATING MEANS FOR MICROSWITCHES Filed Jan. 24, 1964 FIG. #1

2 Sheets-Sheet l INVENTORS 0 7 Kraufj BY FFQJIL Bab/1420 0. KRAUSS ET AL ACTUATING MEANS FOR MICROSWITCHES 2 Sheets-Sheet 2 6%.; G- 5 W i v l I I T INVENTORS 8 0.720 Emu IN" mm! W! BY P 6 United States Patent ACTUATIN G MEANS FOR MICROSWITCHES v Otto Krauss and Franz Bahmann, Numberg, Germany, assignors to Max Grundig, Furth, Bavaria, Germany Filed Jan. 24, 1964, Ser. No. 340,085

Claims priority, application Germany, Jan. 29, 1963,

17 Claims. (Cl. 200 -172) The present invention relates to microswitches.

In particular, the present invention relates to that type of microswitch where a plunger projects from the interior of the switch housing to the exterior thereof and where a lever engages the plunger to displace the latter longitudinally for actuating the switch. In general, this lever may be actuated by any machine element and is supported by a suitable bearing or bracket which is carried by the housing of the switch.

Inasmuch as such levers are subjected to a considerable amount of wear, they are generally mounted so that a worn lever can easily be removed and replaced by a new lever.

However, the frequent changing of such levers is a serious disadvantage and up to the present time attempts to reduce the wear of the levers have been unsuccessful. The end of the plunger in a relatively short time wears a groove in the lever due to the relative sliding between the lever and plunger when the lever turns to displace the plunger. While attempts have been made to choose for the lever and plunger suitable materials to reduce the wear, these attempts have been unsuccessful. Either the plunger or the lever wear away too rapidly or where relatively hard or hardened materials are used, the parts are subject to frequent breakage.

It is accordingly a primary object of the present invention to provide a microswitch construction with a lever of the above type which can easily be replaced but which at the same time will have a rate of wear far less than that which is encountered with conventional microswitches.

In particular, it is an object of the present invention to achieve this result with a construction which greatly reduces the extent to which the lever and plunger slide one relative to the other during turning of the lever to displace the plunger.

It is furthermore an object of the present invention to provide a lever of the type which will securely remain in an operative position on the switch assembly while at the same time being easily removable so as to be replaced whenever required.

Furthermore, it is an object of the present invention to provide an assembly of the above type where the lever will be reliably maintained in its proper operating position.

Also, it is an object of the invention to provide a simple inexpensive structure which will operate reliably to accomplish the above objects.

With these objects in view, the invention includes, in a microswitch, a housing means and a plunger means extending from the interior to the exterior of the housing means and having at the exterior thereof an elongated portion which terminates in an outer end of the plunger means. The plunger means has a longitudinal'axis and is supported by the housing means for movement along this longitudinal axis between a pair of end positions where the outer end of the plunger means intersects the longitudinal axis at a pair of predetermined points, re spectively. An elongated lever means engages the outer end of the plunger means to displace the latter along its longitudinal axis, and a support means is carried by the housing means and supports the lever means for turning movement about a turning axis which is located in a plane normal to the longitudinal axis of the plunger means and Patented August 2, 1966 intersecting this longitudinal axis midway between the above-mentioned predetermined points of intersection of this axis and the outer end of the plunger means when the latter is in its end positions, respectively. As a result of this location of the turning axis of the lever means relative to the outer end of the plunger means the relative slip between the lever means and the plunger means is reduced to a minimum so that wear of the lever means is maintained at a minimum.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1A is a side elevation of one possible embodiment of a microswitch according to the present invention;

FIG. 1B is an end elevation of the structure of FIG. 1A as seen from the left of FIG. 1A;

FIG. 2A is a side elevation and FIG. 2B is an end elevation, from the left of FIG. 2A, of a second embodiment of a microswitch according to the present invention;

FIG. 3A is a side elevation and FIG. 3B is an end elevation, from the left of FIG. 3A, of a third embodiment of a microswitch according to the present invention;

FIG. 4A is a side elevation and FIG. 4B is an end elevation, as seen from the left of FIG. 4A, of a fourth embodiment of a microswitch according to the present invention; and

FIG. 5 is a schematic illustration of the principle of operation of the present invention.

Referring now to FIGS. 1A and 1B, the microswitch illustrated therein includes a housing means 1 carrying a plunger means 9 which projects from the interior to the exterior of the housing means and which has, as shown in FIG. 1A, an elongated portion at the exterior of the housing means 1 terminating in an outer left end, as viewed in FIG. 1A. The plunger 9 has a horizontal longitudinal axis, as viewed in FIG. 1A, and this plunger 9 is supported by the housing means 1 for movement horizontally, as viewed in FIG. 1A, along its longitudinal axis between a pair of end positions where the outer end of the plunger 9 intersects its longitudinal axis at a pair of predetermined points, as will be apparent from the description below in connection with FIG. 5.

An elongated lever means 4 engages the outer end of the plunger 9 to displace the latter along its longitudinal axis so as to actuate the switch in a manner well known in the art. A support means 2 is carried by the housing means 1 and supports the lever means 4 for turning movement about a turning axis A which is located in a plane normal to the longitudinal axis of the plunger 9 and intersecting this latter axis midway between the points of intersection between the outer end of the plunger 9 and this longitudinal axis when the plunger 9 is in its end positions, and this feature, as explained in greater detail below in connection with FIG. 5, results in a minimum amount of wear between the lever 4 and the plunger 9.

The support means 2 takes the form of a bracket fixed to the housing means 1 and having distant therefrom an elongated projection 3 at the side of the lever 4 opposite from the housing means 1. This projection 3 acts as a limiting means to limit the turning of the lever 4 about the turning axis A away from the plunger 9 in a clockwise direction, as viewed in FIG. 1A. The bracket 2 is formed with a cutout, in the form of a slot, through which a portion of the lever 4 extends, and the lever 4 has a pair of shoulders 6 (FIG. 1B) engaging a surface of the bracket 2 which is directed toward the plunger 9 so as to limit the movement of the lever 4 from the plunger 9 toward the bracket 2, In order to maintain the lever 4-in its operative position a lug 5 is struck therefrom at the portion 7 of the lever 4 which projects beyond the bracket 2 at the side thereof directed away from the plunger 9, and this lug 5 engages the surface of the bracket 2 which is directed away from the plunger 9 so as to maintain the lever 4 in its operative position supported by thebracket i 2 for turning movement about the axis A. The portion of the lever 4 which is at the side ofthe bracket 2 which is directed toward the plunger 9 is wider than the length of the slot of the bracket 2 so that the shoulders 6 cannot move through this slot, and the width of the portion 3 7 of the lever 4 is only slightly less than the length of the slot in the bracket 2. In order to remove the lever 4 it I is only necessary to deflect the lug 5 back into the plane of the portion 7 of the lever 4 and then the lever can be slipped downwardly in the direction of the arrow a of 5 FIG. 1B away from the bracket 2. The lever 4 has a cranked portion 8 which enables the axis A to be situated 1 identical with the housing means 1 and the plunger .9: The bracket 12 is the same as the bracket 2 except that it does not have any projection '3. The lever 14 extends in the same way as the lever 4 through a slot of the bracket 12 and has struck from its portion 17 a lug 15 which engages the surface of the bracket 12 which is directed away from the plunger 19 so as to maintain the lever 14 in the illustrated position with the shoulders of the lever. engaging the surface of the bracket 12 which is directed toward the plunger 19. The support means 12 provides for -j the lever means 14 a turning axis A which has with 'respect to the plunger 19 the same relationship as the turning axis A of the lever 4 with respect to the plunger 9. 1 It will be noted that the lever 14 has a cranked portion 18 identical with the cranked portion 8.

The principal distinction of the embodiment of FIGS. 2A and 2B'over that of FIGS. 1A and 1B is that-instead of providing the support means with a projection .3, in the embodiment'of FIGS. 2A and 2B the lever 14. has a lug 16 struck from a portion thereof at the side of'the bracket plunger -19-to serve as a limiting means for limiting the extent to which the lever 14 can turn away from the plunger 19. It will be noted that the lug 16 is located '12 which is directed toward the plunger 19 and engaging the surface of the bracket 12 which is directed toward the at the side of the lever 14 which is directed away from the housing means 11.

With this embodiment it is only necessary to deflect the lug 15 into the plane of the portion 17 of the lever 14 to displace the latter away from the bracket 12 so that the the lever to have at'the bracket 22 the turning axis A which has the above-described relationship with respect to the plunger 29.

In the embodimentof FIGS. 3A and 3B, however, the

portion- 27 of the lever 24 is formed with a cutout 25' having asubstantially H-shaped configuration so that the a cutout has a tongue projecting into the cutout at the side for the bracket 22 directed away from the plunger 29, and at this side of the bracket is located a spring 26; receiving this tongue, situated in the cutoutv 25 ,'"and bearing. against thesurface of the bracket 22 which is directed away from the plunger 29 as well as against the upper edge of the cutout 25, as viewed, in FIGS. 3A and 313, so that the spring 26 urges the. shoulders 30, which correspond to the shoulders 6 of FIG.i1B,againstthe surface of the bracket 22 which'is directed toward the plunger 29. Thus, the spring 26 formsa means urging the lever 24 in the direction of the arrow b of FIG. 3B to maintain the shoulders 30 inengagement with the bracket 22. 1

Because of the H-shaped configuration of the cutout 25 the portion 27: of the lever 24 has a pairiof spaced tongues which project'into' the spring 261, and in order to remove the lever 24 it is:only necessary to displace it downwardly, as viewed in FIG. 313, until the lower tongue of FIG. 3B is displacedbeyond the lower end of the spring 26. after which the latter can be displaced at its; lower end out of the cutout 25f andremoved from the upper tongue of FIG.

3B so thatthe lever 24 .can then be displaced out of'the slot of the bracket 22 in a downwarddirection, :as viewed.

in FIG. 3B.

The embodiment of. FIGS. 4A 'and'4B includes-a housing means .31 and a plunger 39 identical with the. above housing means and plungers of the other embodiments. The bracket, 32"fformsa support'means supporting'the lever 34 for turning movement about the axis A which has with'respect to the plunger 39 the above-described relationship of the axesA of the other embodiments with re In this emand the lever 34 andishookedonto the bracket 32 and 'the lever34 tourgethe latter upwardly and in a clockwise direction about theaxis A,- as viewed in. FIG. 4A,

so that the spring 35 urges-the lever 34, toward the limitmg pro ection 33 and in addition maintainsthe shoulders 36 against the bracket-32; Withthe embodiment of FIGS. 4A and 4B in order to remove the lever 34 it is only necessary to unhook the spring 35 either fromthe bracket 32' or fromthe lever 34. In FIG. 4B,.in ;order to clearly illustrate .the spring 35 part of the; projection 33 is broken away, but its outline is indicated in dot-dash lines."

In all of the above-described embodiments'the brackets, levers, plunger-s and springs may be. made. ofany suitable metals, for example.

The principle of the present inventioniwhich reduces the wear between'the lever. and plunger to a minimum is shownediagrammatically inrFIG. 5. Thus, referring to FIG. 5, plunger 8, corresponding to anyot the above plungers, is supported by thehousing' means.forimove;

ment along the'longitudinal axisEL of the plunger S between the end positionswhere the outer end of the plunger Sintersects the longitudinal axis. L at the: points where thelines R and'Bdntersectthe axis L. These .linesare perpendicular to the axis L so thatthe-distance W there.

between indicatesthe-stroke of the :plunger S when it is displaced between its endipositionsu The lever H corre-' sponding to. the above levers: engages-the plunger S to displace it along its axis IL andis supportedby thesupport means T, corresponding to any of the above brackets and carried by the housing means as described above,

for turning movement'about the axis A which is situated within the plane Etwhichis normal to theaxis L arid. intersectsythe latter midway between the points of=intersection of therouter endof thezplungerS with this. longitudinal axis when the plungeris in its end positions. As aresult of .this arrangement the relative movementbetween the lever H and the plunger S is reduced to a minimum so that the wear between these parts is also reduced to a minimum. Tests have shown that the life of the lever of the invention as well as the plunger is very greatly increased as compared with conventional microswitches.

It will be understood that each of the elements described above, or two or more together, may also find a without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications Without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a microswitch, in combination, housing means; plunger means having an elongated portion projecting from the interior of said housing means and terminating in an outer end, having a longitudinal axis, and supported by said housing means for longitudinal movement along said axis between a pair of end positions where said outer end of said plunger means intersects said longitudinal axis at a pair of predetermined points, respectively; lever means engaging said outer end of said plunger means for displacing the latter along said axis; and support means carried by said housing means and supporting said lever means for turning movement about an axis located in a plane normal to said longitudinal axis of said plunger means and intersecting said longitudinal axis midway between said points.

2. In a microswitch, in combination, housing means; plunger means having an elongated portion projecting from the interior of said housing means and terminating in an outer end, having a longitudinal axis, and supported by said housing means for longitudinal movement along said axis between a pair of end positions where said outer end of said plunger means intersects said longitudinal axis at a pair of predetermined points, respectively; lever means engaging said outer end of said plunger means for displacing the latter along said axis; support means carried by said housing means and supporting said lever means for turning movement about an axis located in a plane normal to said longitudinal axis of said plunger means and intersecting said longitudinal axis midway between said points; and limiting means limiting said lever means to turning movement relative to said support means.

3. In a microswitch, in combination, housing means; plunger means extending from the interior to the exterior of said housing means and having at the exterior of said housing means an elongated portion terminating in an outer free end of said plunger means, said plunger means having a longitudinal axis and being supported by said housing for movement along said longitudinal axis between a pair of end positions where said outer end of said plunger means intersects said longitudinal axis at a pair of predetermined points; elongated lever means engaging said outer end of said plunger means for displacing the latter along said axis; and support means supporting said lever means for turning movement about a turning axis which is located in a plane normal to said longitudinal axis and intersecting the latter midway between said points, said support means including a bracket fixed to said housing means and formed with an opening through which said lever means extends and said lever means having a lug projecting therefrom and engaging said bracket to limit movement of said lever means in at least one direction relative to said bracket transversely of said turning axis.

4. In a microswitch, in combination, housing means; a plunger extending from the interior to the exterior of said housing means, having at the exterior of said housing means an elongated portion terminating in an outer end of said plunger, having a longitudinal axis and being supported by said housing means for movement along said axis between a pair of end positions where said outer end intersects said axis at a pair of predetermined points; an elongated lever engaging said outer end of said plunger for displacing the latter along said axis; a bracket carried by said housing means and formed with a cutout through which said lever extends, said lever having a shoulder engaging said bracket at a surface of the latter directed toward said plunger to limit movement of said lever in a direction from said plunger toward said bracket, and said bracket supporting said lever for turning movement about an axis located in a plane normal to said longitudinal axis and intersecting the latter midway between said points; and means operatively connected to said lever for maintaining said shoulder thereof in engagement with said bracket.

5. In a microswitch as recited in claim 4, said lastrnentioned means including a lug projecting from said lever and engaging a surface of said bracket which is directed away from said plunger.

6. In a microswitch, in combination, housing means; a plunger extending from the interior to the exterior of said housing means, having at the interior of said housing means an elongated portion terminating in an outer end of said plunger, having a longitudinal axis and being supported by said housing means for movement along said axis between a pair of end positions where said outer end intersects said axis at a pair of predetermined points; an elongated lever engaging said outer end of said plunger for displacing the latter along said axis; a bracket carried by said housing means and formed with a cutout through which said lever extends, said lever having a shoulder engaging said bracket at a surface of the latter directed toward said plunger to limit movement of said lever in a direction from said plunger toward said bracket, and said bracket supporting said lever for turning movement about an axis located in a plane normal to said longitudinal axis and intersecting the latter midway between said points; and spring means operatively connected to said lever for urging the latter from said plunger toward said bracket so as to maintain said shoulder thereof in engagement with said bracket.

7. In a microswitch, in combination, housing means; plunger means extending from the interior to the exterior of said housing means and having at the exterior of said housing means an elongated portion terminating in an outer end of said plunger means, said plunger means having a longitudinal axis and being supported by said housing means for movement along said longitudinal axis between a pair of positions where said outer end of said plunger means intersects said longitudinal axis at a pair of predetermined points; elongated lever means engaging said outer end of said plunger means for displacing the latter along said longitudinal axis; support means carried by said housing means and supporting said lever means for turning movement about a turning :axis located in a plane normal to said longitudinal axis and intersecting the latter midway between said points; and limiting means limiting the extent to which said lever means can turn away from said plunger means.

8. In a microswitch as recited in claim 7, said limiting means including a portion of said support mean-s located in the path of turning of said lever means away from said plunger means.

9. In a microswitch as recited in claim 7, said limiting means including a lug projecting from said lever means Q and engaging said support means to limit the extent to which said lever means can turn away from said plunger means.

10. 'In a microswitch, in combination, housing means; a plunger extending from the interior to the exterior of said housing means and having an elongated portion at the exterior of said housing means terminating in an outer end of said plunger, said plunger having a longitudinal axis and being supported by said housing means for movement along said axis between a pair of end positions Where said end of said plungerintersects said axis at a pair of predetermined points; an elongated lever engaging said outer end of said plunger for displacing the latter along said axis; a bracket fixed to said housing means and formed with a cutout through which said lever extends, said lever having a shoulder engaging said bracket at a surface thereof which is directed toward,

said plunger to limittmovement of said lever from said plunger toward said bracket and said bracket supporting said lever [for turning movement about a turning .axis located in a plane normal to said longitudinal axis and intersecting the latter midway between said points, said lever having a portion projecting beyond said bracket at the side thereof opposite from-said plunger and formed with an opening extending at least up to said bracket, said lever having a tongue projecting into said opening and directed toward said bracket at the side thereof which is directed away from said plunger; and a coil spring in said opening surrounding said tongue and engaging said lever and bracket to urge said shoulder of said lever against said bracket.

11. In a microswitch as recited in claim 10, said bracket having at the side of said lever which is directed away:

from said housing means a projection limiting turning of said lever away from said housing means.

12. In a microswitch, in combination, housing means; a plunger extending from the interior to the exterior of said housing means and having an outer elongated portion at the exterior of said housing means terminating in an outer end of said plunger, said plunger having a :longitudinal axis and being supported by said housing means for movement along said longitudinal axis between a pair .ing movement about a turning axis located in a plane normal to said longitudinal axis and intersecting the latter midway between said points, and said lever having at a portion which projects beyond said bracket at the side.

thereof opposite from said plunger a lug engaging a surface of said bracket'which is directed away from said plunger.

13. In a microswitch as recited in claim 12, said bracket having at the side of said lever which is directed away from said housing means a projection limiting the turn-. ingot said lever away from said plunger,

:BERNARD. A. GILHEANY,KATHLEENHrC F s 14. In a microswitch as recited in claim 12, isaid lever having at the; side of said bracket which is directed 'toward said' plunger a second lug projecting-from said lever away from said housing means and engaging said'surface of said bracket'which is directed toward saidplunger, to

limit turning of said lever away from said plunger.

15. In a microswitch; in-combinationhousing means;

a plunger extending from the interior to the exterior of said housing means and having at: the exterior of said housing means an elongated portion terminating in an outer-end of said: plunger, said plunger having a longitudinal-axis and being. supported by said housing means for movement along said longitudinal axis between a pair of end positions where said outer end. of said plunger'intersects saidaxis at a pair of predetermined points; an elongated lever engaging said 'outer endof said plungerqfor displacing the' latter along said longitudinal axis; a bracket fixed to and projecting from saidhousing means and formed with a cutout through which'said leverv extends, said lever having a shoulder engaging a surface of said bracket which is directed toward said plunger to limit movement of said lever from-said plunger toward said bracket, said bracket supporting said lever for turning movement-about a turning axis located in a plane normal to said longitudinal axis and intersecting the latter midway betweensaid points; and an elongated coil spring connected at one end to said lever and at an opposite end to said bracket for urging said shoulder of saidlever toward said bracket.

16. In a microswitch as recited in claim 15, isaidibracke;

et having at the side of said lever which. is directed away -from said housing means a projection limiting turning of said lelver away fromzsaid plunger, and said spring being located between said-projection and said lever and urging the latter to turn away vfrom said plunger into engage-- ment with said projection.

17. In a microswitch, in combination, support means; plunger means having an outer end, having a longitudinal axis, and supportedby saidsupp'ort meansifor longitudia nal movement along said axis between a pair of end positions where said outer end of said plunger means intersects said longitudinal axis .at a pair of predetermined points, respectively;.lever-means engaging said outer end of said plunger means for'displacing the latter along said 'axis; and bearing means supporting said lever means for turning movement about an axis located in -a plane normal to said longitudinal axis of said plunger means and.

intersecting saidlongitudinal axis intermediate said points whereby relative sliding movement between i said lever means and said outer end of said pluger means is reduced to a minimum.

References Cited by the Examiner UNITED STATES PATENTS 2,828,372 3/195s- Bulgin'. 2,898,428 8/1959 Holden I 200172 ROBERT K. SCHAEFER, Primary Examiner.

Examiners. H. O. JONES, Assistant Examiner.= 

1. IN A MICROSWITCH, IN COMBINATION, HOUSING MEANS; PLUNGER MEANS HAVING AN ELONGATED PORTION PROJECTING FROM THE INTERIOR OF SAID HOUSING MEANS AND TERMINATING IN AN OUTER END, HAVING A LONGITUDINAL AXIS, AND SUPPORTED BY SAID HOUSING MEANS FOR LONGITUDINAL MOVEMENT ALONG SAID AXIS BETWEEN A PAIR OF END POSITIONS WHERE SAID OUTER END OF SAID PLUNGER MEANS INTERSECTS SAID LONGITUDINAL AXIS AT A PAIR OF PREDETERMINED POINTS, RESPECTIVELY; LEVER MEANS ENGAGING SAID OUTER END OF SAID PLUNGER MEANS FOR DISPLACING THE LATTER ALONG SAID AXIS; AND SUPPORT MEANS CARRIED BY SAID HOUSING MEANS AND SUPPORTING SAID LEVER MEANS FOR TRUNING MOVEMENT ABOUT AN AXIS LOCATED IN A PLANE NORMAL TO SAID LONGITUDINAL AXIS OF SAID PLUNGER MEANS AND INTERSECTING SAID LONGITUDINAL AXIS MIDWAY BETWEEN SAID POINTS. 